Process for avoiding color fog on photographic color material



Jan. 26, 1943. F. ALBERS EI'AL 2,309,492

PROCESS FOR AVOIDING COLOR FOG ON PHOTOGRAPHIC COLOR MATERIAL Filed Aug. 13, 1940 AG-HAL/DE EMULSION LAYER CONTAIN/N6 COLOR F RMING DEVELOPMENT COMPONENT AND AN ALDEHYDE REACTIVE COMPOUND 0F THE GROUP CONS/STING 0F HYDROXYL AMINES, HYDRAZO co/wpo unmsw yo fiAZ/N Es, SEMICARBAZ 05s, NAPHTHALENE D/A M IN 55 BAR/UM SULFATE LAYER BASE CONTAINING ALDEHYDE HARDENINGAG'ENT FRITZ ALsERs A/vu AF/VED FHDHLIGH l/V/LHELM SCHNEIDER A/vfl fRw/N TRA BER T Patented Jan. 26 1943 PROCESS FOR AVOIDING COLOR FOG ON PHOTOGRAPHIC COLOR MATERIAL Fritz Albers, Leverkusen-Wiesdorf, Alfred Friihlich and Wilhelm Schneider, Dessau, and Erwin Trabert, Leverkusen-Wiesdorf, Germany, assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application August'13, 1940, Se'rialNo. 352,402 In Germany July 14, 1939 12 Claims.

This invention relates to a processfor avoiding color-fog on photographic color material.

It is customary to use formaldehyde almost exclusively for the hardening of photographic emulsion layers, especially also of photographic papers. Also when manufacturing raw-paper and casting the bariumsulfate layer for photographic paper, formaldehyde is employed. If blackand-white-images are produced in such layers, the traces of formaldehyde remaining in the photographic material are not disturbing. It was found, however, that traces of formaldehyde influence considerably the whites of photographic emulsion layers containing color formers. The cause for it lies in the reactivity of the formaldehyde and other aldehydes with the color formers serving for the production of the color image. Pyrazolones for instance react with formaldehyde and oxidizing substances with the formation of tensely yellow-colored compounds. Since slight traces of formaldehyde are suificient to produce the undesired color-fog, it is extremely difficult to eliminate the formaldehyde in the manufacturing process to such an extent, that no detrimental consequences appear.

It is an object of this invention to produce photographic color materials being free from color-fog.

Another object is the manufacture of photographic color paper which is free from colorfog.

These and other objects will become apparent from the following specification. I

It has been found that it is possible to avoid the undesired color-fog in color photographic fog in the emulsion nor decrease its sensitivity nor precipitate or deluster the emulsion. Suit-' able substances are for instance hydroxyl amines, hydrazine derivatives, for instance hydrazinesulfo acid, hydrazine dicarboxylic acid ethyl ester, i'n-methylhydrazine, a-quinolylhydrazine,

cyanacetylhydrazine, hydrazo derivatives, for instance hydrazoisobutyro nitrile, semicarb aai des, forinstance semi-carbazide hydrochloride, 1,4- phenylsemicarbazide, dimethylhydroresorcin and naphthylene diamines, for instance 1,8-naphthylene diaminel-sulfo acid.

The photographic emulsion layers contain color formers reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, preferably those fast to diffusion according to the following U. S. patents: 2,178,612, 2,179,238, 2,179,244, 2,186,732, 2,186,8'z9, 2,186,850 and 2,280,772; and U. S. application Ser. No. 327,628, filed April 3, 1940, applied for on behalf of Frtilich et al.

The invention is further illustrated by the following example when taken with the accompanying self-explanatory drawing depicting in section a film according to the present invention.

To 1 kg. silver halide emulsion containing a pyrazolone derivative as color former there is added 1-2 grams of semicarbazide hydrochloride. This mixture is cast onto a support in a manner known per se.

Neither during the manufacturing process nor during prolonged storage could a color-fog be observed on these emulsion layers.

What we claim is 1. In a method of processing photographic colormaterial comprising a support carrying a silver halide emulsion layer containing a color former reactivelwit h the oxidation products of an aromatic amino'developer-to form a dye in situ with the silver image, and an aldehyde hardening agent for the emulsion tending to react Wit1l. said color former to produce color fog, the

improvement which comprises inhibiting the formation of said color fog by contacting said color material with an organic substance reactive with the aldehyde hardening agent and selected from the" class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.

2. Photographic color material comprising a support carrying a silver halide emulsion'layer containing a color former reactive with the oxi dation products of an aromatic amino developer to form a dye in situ with the silver image, and an aldehyde hardening agent tending to react with said color former to produce color fog, said material also containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.

3. A photographic material for color forming development comprising a support layer, at least one silver halide emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer, and a backing layer, at least one of said layers containing traces of an aidehyde hardening agent having the tendency to produce color fog with said color former, at least one of said layers containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.

4. A photographic material for color forming development comprising a support layer substantially consisting of a paper support and a barium sulfate layer, at least one silver halide gelatin emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer, and a backing layer, said paper support and said emulsion layer containing traces of an aldehyde hardening agent having the tendency to produce color fog with said color former said paper least one of said layers an aldehyde hardening agent tending to react with the color former to produce color fog, and said gelatino silver halide emulsion also containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-.- carbazides, naphthalene diamlnes and dimethylhydroresorcines.

'7. Multi-color photographic paper comprising a gelatino silver halide emulsion layer containing a color former reactive with the oxidation products of an aromatic developer to form a dye in situ with the silver image, a barium sulfate layer, and-a paper support for the photographic emulsion and the barium sulfate layer, said photographic material containing in at least one of said layers an aldehyde-hardening agent tending to react with the color former to produce color fog, said barium sulfate layer containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo support additionally containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of'hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.

5. A photographic material for color forming development comprising a support layer substantially consisting of a paper support and a barium sulfate layer, at least one silver halide gelatin emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer and a backing layer, said barium sulfate layer and said emulsion layer containing traces of an aldehyde hardening. agent having the tendency to produce color fog with said color former, .said barium sulfate layer additionally containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-carbazides, naphthalene diamines, and dimethylhydroresorc'ines.

photographic emulsion and said barium sulfate layer, said photographic paper containing in at compounds, semi-carbazides, naphthalene diamines, and dimethylhydroresorcines.

8. A multi-color photographic paper compris-- sulfate layer, at least one of said layers 'containing an aldehyde hardening agent, tending to react with the color former to produce color fog, said paper support containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-carbazides, naphthalene diamines, and dimethyldroresorcines.

9. The process as defined in claim 1 wherein the organic substance reactive with the aldehyde hardening agent is a seml-carbazide.

10. The article as defined in claim 2 wherein the organic substance reactive with the aldehyde hardening agent is a semi-carbazide.

11. The article as defined in claim 2 wherein the organic substance reactive with the aldehyde hardening agent is a semi-carbazide and the color former is a pyrazolone.

12. The article as defined in claim 2 wherein the organic substance reactive with the aldehyde hardening agent is semi-carbazidehydrochloride and the color former is a pyrazolone.

FRITZ ALBERS. ALFRED mormrcn. W'ILI-IEIM SCHNEIDER. ERWIN TRABERT.

CERTIFICATE OF CORRECTI ON Patent No. 2,509,192. January 26, 1915.

FRITZ ALBERS, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, sec- .ond column, line 5859, claim 8, for "dimethyldroresorcines" read dimethylhydroresorcines; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 11mm day of December, A. D. 19%.

Henry Van Arsdalew, (Seal) Acting Commissioner of Patents. 

